.box{
    width: 300px;
    height: 100%;
    background-color: #ddd;
    margin: 200px auto;
}
.top{
    display: flex;
    justify-content:space-between;
    padding: 10px;
    border-bottom: 1px solid gray;
}
.main{
    padding-left: 20px;
    padding-bottom: 20px;

}
body{
    background-color: #fff;
}